/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/********************************************************************************
 * kernel/timer/timer_create.c
 *
 *   Copyright (C) 2007-2009, 2011, 2014 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ********************************************************************************/

/********************************************************************************
 * Included Files
 ********************************************************************************/

#include <tinyara/config.h>

#include <stdint.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include <errno.h>

#include <tinyara/wdog.h>
#include <tinyara/kmalloc.h>

#include "timer/timer.h"

#ifndef CONFIG_DISABLE_POSIX_TIMERS

/********************************************************************************
 * Definitions
 ********************************************************************************/

/********************************************************************************
 * Private Data
 ********************************************************************************/

/********************************************************************************
 * Public Data
 ********************************************************************************/

/********************************************************************************
 * Private Functions
 ********************************************************************************/

/********************************************************************************
 * Name: timer_allocate
 *
 * Description:
 *   Allocate one POSIX timer and place it into the allocated timer list.
 *
 ********************************************************************************/

static struct posix_timer_s *timer_allocate(void)
{
	struct posix_timer_s *ret;
	irqstate_t flags;
	uint8_t pt_flags;

	/* Try to get a preallocated timer from the free list */

#if CONFIG_PREALLOC_TIMERS > 0
	flags = irqsave();
	ret = (struct posix_timer_s *)sq_remfirst((sq_queue_t *)&g_freetimers);
	irqrestore(flags);

	/* Did we get one? */

	if (ret) {
		pt_flags = PT_FLAGS_PREALLOCATED;
	} else
#endif
	{
		/* Allocate a new timer from the heap */

		ret = (struct posix_timer_s *)kmm_malloc(sizeof(struct posix_timer_s));
		pt_flags = 0;
	}

	/* If we have a timer, then put it into the allocated timer list */

	if (ret) {
		/* Initialize the timer structure */

		memset(ret, 0, sizeof(struct posix_timer_s));
		ret->pt_flags = pt_flags;

		/* And add it to the end of the list of allocated timers */

		flags = irqsave();
		sq_addlast((sq_entry_t *)ret, (sq_queue_t *)&g_alloctimers);
		irqrestore(flags);
	}

	return ret;
}

/********************************************************************************
 * Public Functions
 ********************************************************************************/

/********************************************************************************
 * Name: timer_create
 *
 * Description:
 *   The  timer_create() function creates per-thread timer using the specified
 *   clock, clock_id, as the timing base. The timer_create() function returns, in
 *   the location referenced by timerid, a timer ID of type timer_t used to identify
 *   the timer in timer requests. This timer ID is unique until the timer is
 *   deleted. The particular clock, clock_id, is defined in <time.h>. The timer
 *   whose ID is returned will be in a disarmed state upon return from
 *   timer_create().
 *
 *   The evp argument, if non-NULL, points to a sigevent structure. This structure
 *   is allocated by the called and defines the asynchronous notification to occur.
 *   If the evp argument is NULL, the effect is as if the evp argument pointed to
 *   a sigevent structure with the sigev_notify member having the value SIGEV_SIGNAL,
 *   the sigev_signo having a default signal number, and the sigev_value member
 *   having the value of the timer ID.
 *
 *   Each implementation defines a set of clocks that can be used as timing bases
 *   for per-thread timers. All implementations shall support a clock_id of
 *   CLOCK_REALTIME.
 *
 * Parameters:
 *   clockid - Specifies the clock to use as the timing base.
 *   evp - Refers to a user allocated sigevent structure that defines the
 *     asynchronous notification.  evp may be NULL (see above).
 *   timerid - The pre-thread timer created by the call to timer_create().
 *
 * Return Value:
 *   If the call succeeds, timer_create() will return 0 (OK) and update the
 *   location referenced by timerid to a timer_t, which can be passed to the
 *   other per-thread timer calls.  If an error occurs, the function will return
 *   a value of -1 (ERROR) and set errno to indicate the error.
 *
 *   EAGAIN - The system lacks sufficient signal queuing resources to honor the
 *    request.
 *   EAGAIN - The calling process has already created all of the timers it is
 *     allowed by this implementation.
 *   EINVAL - The specified clock ID is not defined.
 *   ENOTSUP - The implementation does not support the creation of a timer attached
 *     to the CPU-time clock that is specified by clock_id and associated with a
 *     thread different thread invoking timer_create().
 *
 * Assumptions:
 *
 ********************************************************************************/

int timer_create(clockid_t clockid, FAR struct sigevent *evp, FAR timer_t *timerid)
{
	struct posix_timer_s *ret;
	WDOG_ID wdog;

	/* Sanity checks.  Also, we support only CLOCK_REALTIME */

	if (!timerid || clockid != CLOCK_REALTIME) {
		set_errno(EINVAL);
		return ERROR;
	}

	/* Allocate a watchdog to provide the underling CLOCK_REALTIME timer */

	wdog = wd_create();
	if (!wdog) {
		set_errno(EAGAIN);
		return ERROR;
	}

	/* Allocate a timer instance to contain the watchdog */

	ret = timer_allocate();
	if (!ret) {
		wd_delete(wdog);
		set_errno(EAGAIN);
		return ERROR;
	}

	/* Initialize the timer instance */

	ret->pt_crefs = 1;
	ret->pt_owner = getpid();
	ret->pt_delay = 0;
	ret->pt_wdog = wdog;

	if (evp) {
		ret->pt_signo = evp->sigev_signo;
#ifdef CONFIG_CAN_PASS_STRUCTS
		ret->pt_value = evp->sigev_value;
#else
		ret->pt_value.sival_ptr = evp->sigev_value.sival_ptr;
#endif
	} else {
		ret->pt_signo = SIGALRM;
		ret->pt_value.sival_ptr = ret;
	}

	/* Return the timer */

	*timerid = ret;
	return OK;
}

#endif							/* CONFIG_DISABLE_POSIX_TIMERS */
